STAINLESS STEEL MATERIAL GRADE

Stainless steel fasteners are particularly popular in the automotive industry, which involves stainless steel screws in the construction of structural automotive components.
Because automobiles are subject to variable weather conditions and hazardous contaminants like salt in some cases, stainless steel is an excellent fastener composition; it resists weather and salt-induced oxidation. For these and other reasons, stainless steel screws are also used in the electronics manufacturing, medical products, watercraft building and construction industries.
Stainless steel alloys are iron-based metals containing at least 10% chromium and other metals, which provide added corrosion and heat resistance. They do not require a protective coating, and they are able to perform well in a wide range of conditions and temperatures.

 


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Stainless Steel

We are the biggest producers for stainless steel bolts and nuts in India, as our name suggests we are manufacturing big bolts and nuts in stainless steel grades in the under mentioned table.

Fastener Type

Diameter

Grades

Grades

Grades

Grades

Hexagon bolts

M-12 to M-100

304 / 304 L

316 / 316 L

310 / 310 S

410 / 431

Hex bolts

M-12 to M-100

304 / 304 L

316 / 316 L

310 / 310 S

410 / 431

Hex cap screws

M-12 to M-100

304 / 304 L

316 / 316 L

310 / 310 S

410 / 431

Socket head cap screws

M-30 to M-72

304 / 304 L

316 / 316 L

310 / 310 S

410 / 431

Hex nuts

M-30 to M-72

304 / 304 L

316 / 316 L

310 / 310 S

410 / 431

Hex lock nuts

M-30 to M-72

304 / 304 L

316 / 316 L

310 / 310 S

410 / 431

Hex nylock nuts

M-30 to M-64

304 / 304 L

316 / 316 L

310 / 310 S

410 / 431

Hex castle nuts

M-12 to M-72

304 / 304 L

316 / 316 L

310 / 310 S

410 / 431

Heavy hex nuts

M-12 to M-72

304 / 304 L

316 / 316 L

310 / 310 S

410 / 431

Washers

M-12 to M-72

304 / 304 L

316 / 316 L

310 / 310 S

410 / 431

Stud bolts

M-12 to M-72

304 / 304 L

316 / 316 L

310 / 310 S

410 / 431

Comparison chart for international steel grades for stainless steel bolting’s

Grades

European Number

ASTM grade

UNS

British standard

DIN

304

1.4301

ASTM A 193 Gr B8

S 30400

BS 970

X 5CrNi1810

304 L

1.4306

ASTM A 320 Ge B8

S 30403

BS 970

X 2CrNi1911

316

1.4401

ASTM A 193 Gr B8M

S 31600

BS 970

X 5 CrNiMo 17 13 2

316 L

1.4404

ASTM A 320 Ge B8M

S 31603

BS 970

X 2 CrNiMo 17 13 2

310

1.4841

ASTM A 479

S 31000

BS 970

X 12 CrNi 25 21

310 S

1.4845

 

S 31008

BS 970

X 12 CrNi 25 21

410

1.4006

 

S 41000

BS 970

X 10Cr13

431

1.4057

 

S 43100

BS 970

X 20CrNi172

316S31

1.4401

ASTM A 193 Gr B8M

S 31600

BS 970

X 5 CrNiMo 17 12 2

Stainless steel can be broken down into three different types: Austenitic, Martensitic and Ferritic.

•   Austenitic Stainless Steel
(Between 15%-20% Chromium, Between 5%-19% Nickel) - Austenitic stainless has the highest degree of corrosion resistance of the three types. This type of stainless includes these grades: 302, 303, 304, 304L, 316, 32, 347 and 348. They also have a tensile strength of between 80,000 - 150,000 PSI.

•   Martensitic Stainless Steel
(Between 12%-18% Chromium) - Martensitic stainless steel is considered a magnetic steel. It can be heat treated to increase its hardness and is not recommended for welding. This type of stainless includes: 410, 416, 420 and 431. They have a tensile strength of between 180,000 and 250,000 PSI.

•   Ferritic Stainless Steel
(Between 15%-18% Chromium) - Ferritic stainless steel has a tensile strength of 65,000 - 87,000 PSI. While it is still corrosion resistant, it is not recommended for areas where corrosion is likely to occur. This material cannot be heat treated. Due to the forming process it is magnetic and not suitable for welding. Ferritic grades of stainless include: 430 and 430F.stainless-steel2.jpgBelow are some of the many bolt grades of stainless steel that we carry.

a ) 18-8 Stainless Steel:
(18% Chrome, 8% Nickel, .08% Maximum Carbon) - 18-8 Stainless refers to 300 series stainless steel. 303 and 304 Stainless are the most commonly listed grades, the standard grade for stainless fasteners. They are corrosion-resistant and durable. They are often used in marine applications in freshwater environments but will not work as effectively in a salt-water environment as 316 stainless. Stainless alloy resists oxidizing and rusting, however it can tarnish over time. Equivalent to metric A2 Stainless Steel.

b ) 305 Stainless Steel:
(17%-19% Chrome, 8%-10% Nickel, .12% Maximum Carbon) - This grade has been developed specifically to improve the cold heading qualities of 18-8. Corrosion resistance and physical qualities are equal to Type 304. 305 stainless steel is most commonly used to make deck screws, which are used to fasten wood or composite boards to the main beams of a deck.

c ) 316 Stainless Steel:
(16%-18% Chrome, 10%-14% Nickel, .08% Maximum Carbon, 2.00% Maximum Molybdenum) - This grade of steel is used and recommended for applications in severe, harsh or marine environments. Its corrosion resistance is greater than 18-8 stainless, which is why we recommend using 316 stainless steel fasteners for salt-water application. It is important to remember that even the salt in the air near a body of salt-water can do damage to dry applications, so 316 is the material of choice. Common applications of 316 stainless fasteners include use on boats, docks, piers, and pools.

d ) 410 Stainless Steel:
(11.5%-13.5% Chrome, .15% Maximum Carbon) - Since this grade of stainless steel can be hardened up to approximately 40 Rockwell C, it is durable in most environments. Harder than 18-8 stainless but with less corrosion resistance, 410 stainless is commonly used to make roofing screws, siding screws and self-

Over the past few years we have manufactured many different kind of stainless steel grades of bolts and nuts, however the above grades mentioned in the table are the main grades which we are manufacturing consistently. With constant improvement in quality we have been able to excel in the manufacturing process for the above steels and their respective grades.
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Big Bolt Nut is the biggest and the largest producer for stainless steel ( SS ) hex bolts, hex screws, hex nuts, washers in India, we have 2 factories with a total covered area of over 100,00 sq. feet. We produce all types of SS products which are used in marine, sewage, water and desalination plants in counties like, Oman, U.A.E., Qatar, Dubai, Bahrain, Saudi Arabia. Our popular Stainless steel bolts and nuts, SS 304 bolts and nuts, 304 fasteners, 304 Nuts and bolts, 304 bolt nut, 304 nut bolt, 316 Bolts and nuts, 316 fasteners, 316 hex bolts, 316S31 bolts and nuts, stainless fasteners.